As for a prior art, there is an advance and retraction type feed rod, which is provided at its front end with parts holding means comprising a hole or chuck mechanism, said rod including a mechanism disposed on the axis thereof for temporarily locking a part, such as a bolt, coming from a parts feeder or the like, said rod being advanced toward said part in the locked state and, with said holding means holding the part, conveying the part to an intended place.
According to the prior art described above, a single mechanism has to perform two functions at the same time; first, it has to stop a part conveyed from a parts feeder or the like through a feed hose and must be stopped accurately on the axis of the feed rod, and second, the stopped position must be reliably maintained. Therefore, such mechanism is necessarily of high precision, and even a slight decrease in precision would upset the correct engagement between the holding means of the feed rod and a part, causing the problem of the part falling off. Further, if the mechanism for temporarily locking a part is present on the axis of the feed rod all the time, this limits the installation space therefor to a great extent, and hence the device is increased in size, making it difficult to install it in a narrow space.